13 At twelve o'clock the trucks were being loaded by the workers.
14 By three o'clock the trucks had been loaded by the workers.
15 Our daughter is sent to rest in the south every year.
16 This film will be shown on TV.
17 A new concert-hall is being built in our street.
18 A number of important experiments have been made in this laboratory.
19 Central Africa was explored by Livingstone in the 19th century.
20 By the middle of autumn all the trees had been planted.
21 This play will be staged at the beginning of next season.
22. The story has been forgotten.
23 Have you been explained the rules of the game?
24 My skates haven't been brought back.